Conventionally, when a failure occurs in an IP network, search for the cause and location of the network failure is performed with a failure diagnosis tool connected to the network and diagnosis IP packets are transmitted from the tool. In addition, a test command is periodically issued to monitor the operational status of devices connected to the network and to obtain the network configuration information. The test command includes obtaining MIB (Massage Information Base) information by SNMP (Simple Network Management Protocol), a trace route command, and the like.
However, the conventional failure information collection technique, which uses the failure diagnosis tool or test commands as described above, has a problem that communication with traffic that is not originally required for the network services such as Web services and IP telephone services (a series of transmission/reception of IP packets) is required only for searching for the cause and location of the failure. For this reason, according to the management policy of the network, Web services and IP telephone services may be congested due to traffic that is not originally required for users of the network service, and it is not allowed to transmit the traffic for searching for the cause or location of the failure since the influence of the failure may be increased. As a result, there has been a problem that it is difficult to detect the situation in which the failure is occurring, and it may takes a long time to fix the failure.
As related techniques, configuration or method to switch communication modes according to the communication quality and communication situation has been proposed (for example, Japanese Laid-open Patent Publication No. 2006-319520, Japanese Laid-open Patent Publication No. 2001-36937, Japanese Laid-open Patent Publication No. 2005-286777). However, these conventional techniques do not relate to the configuration or method to perform collection of failure information without having influence on the operation of network services such as Web services and IP telephone services.